Clostridial diseases

Leptospirosis

Leptospirosis is an infectious disease caused by bacteria of the Leptospirosis family. It is important, because although it can cause disease in cattle, it is a zoonosis and can cause serious disease in people. Milkers and freezing workers are particularly at risk because it is spread in urine and handling kidneys at slaughter.There are three main serotypes:

Leptospira pomona.L. pomona naturally occurs in pigs, and can be spread to cattle causing abortion in cows, and red-water in calves. Control is by limiting cattle exposure to pigs, and pig effluent, and by vaccinating cattle.

Leptospira hardjo.L. hardjo naturally occurs in cattle, and although any disease associated with this in cattle is mild (mild, chronic and sub-fertility), it is one of the very common sources of infection to people from carrier cows. Control is by vaccination.

Leptospira icterohaemorrhagiae(also known as Leptospira copenhageni). L copenhageni naturally occurs in the brown rat. Control is by controlling rats, and vaccination.

Bovine Virus Diarrhoea (BVD)

This is a serious economic disease of cattle. It is caused by the BVD virus and it is very infectious between cattle. Normally infection of young stock is not a problem because the infected cattle may be off colour for a few days, recover and gain natural immunity.

However, if a pregnant cow gets affected for the first time, the infection spreads to the unborn calf which because of its poor immune status, does not recognize the virus as a foreign pathogen. The unborn calf becomes infected and once it is born, sheds the virus for the rest of its life. The calf however, does not thrive, but once the diagnosis is made, the damage is done.

Pregnant heifers and cows infected for the first time in many cases abort, being a source of serious economic loss to the farmer.

Control is by blood testing, monitoring bulk milk samples, and a vaccination program.

Pink Eye

Pink eye is caused by a bacteria and is spread through cattle by close contact and flies. Pink eye can be a serious disease of cattle. It often appears when mobs have been mixed such as heifers at grazing, and beef farmers trading stock. The main effect of the pinkeye is the pain and suffering that accompanies this condition.There is a vaccine available to aid in the control of this disease.

Infectious bovine rhinotracheitis (IBR)

IBR is a disease caused by the IBR virus. The disease causes a nasal discharge in cattle which is irritating to them. The can rub their noses on sticks which become lodged high in the nasal passages. It can also be a cause of secondary bacterial pneumonia in cattle.

A vaccine is available when IBR becomes a problem in a herd.

Rotavirus

Rotavirus is a serious disease of young calves. Calves are infected by their mothers, soon after birth. Parvovirus can cause severe diarrhoea in calves with high infection rates and in some cases high death rates.

There is a vacine available against Rotavirus for use in adult cattle.